Piperazine salts, such as the aminoethylpiperazine salt of diphenyl ether disulfonic acid, are known in the prior art. For example, U.S. Pat. No. 5,262,535 discloses that these salts are useful as cleaning agents for such articles as plastics and vinyl. Likewise, certain 2-piperazinones (which contain keto-substitution on the ring) are disclosed in compositions containing an alkali metal, alkaline earth metal, or ammonium salt of alkylated diphenyl oxide sulfonate as a surfactant, alone or in combination with a nonionic surfactant that may contain a mixture of ethoxylated and propoxylated alcohol, as taught in U.S. Pat. No. 5,196,146. The '146 patent teaches that the compositions disclosed therein are useful in cleaning grease and oil from metal, plastic, glass, and other surfaces. However, the present inventors have found that the 2-piperazinones disclosed in the '146 patent do not react, in accordance with the preparation process of that patent, with the diphenyl oxide sulfonate surfactant disclosed therein to provide the corresponding piperazinone salt of diphenyl ether disulfonic acid.
There is an need in the marketplace for additives that are useful in enhancing the bonding efficacy of adhesives, and in improving the cleaning efficacy of hard surface cleaners, such as concrete cleaners. The present invention provides one solution to these needs.